I'm trying to use try and except in django; everything work perfect if the user exist but if the user doesn't exist instead of returning NULL; my function keep returning:
Userprofile matching query does not exist.
I know the user is not exist in table; I just want to not return anything instead of showing error page.
from django import template
from album.models import Album
from django.shortcuts import get_object_or_404, render
register = template.Library()
#register.inclusion_tag('album/user_album.html')
def userAlbumFunction(id):
try:
albums = Album.objects.filter(user_id = id)
except Album.DoesNotExist:
albums = None
return {'albums' : albums}
try:
albums = Album.objects.get(user_id = id)
except Album.DoesNotExist:
albums = None
pass
Related
Getting an error always
The current path, <code>api/det/1</code>, didn’t match any of these.
My urls.py
url(r'^api/det/<int:id>',views.DetailsAPI.as_view(),name='DetailsAPI')
My views.py
class DetailsAPI(APIView):
def get(self,id):
filter_list=Details.objects.all()
#filter_list = Details.objects.get(id=id)
envid = self.kwargs['id']
df = read_frame(filter_list)
df_det = df.loc[df['Id'] == int(id)]
df_final=df_det.to_json(orient='records')
return HttpResponse(df_final, content_type = 'application/json')
I'm sure there is some simple stuff that i'm missing and i can't get it to work with whatever syntax i try.. Any suggestions?
Changing the url to the below one worked.
url(r'^api/det/(?P<id>\d+)',views.DetailsAPI.as_view(),name='DetailsAPI')
Seemingly simple situation:
Django model has foreign key:
class Invite(models.Model):
inviter = models.ForeignKey(User, on_delete=models.CASCADE)
...
In async context, I do:
# get invite with sync_to_async decorator, then
print(invite.inviter)
Get async's favorite error:
You cannot call this from an async context - use a thread or sync_to_async
print(sync_to_async(invite.inviter)) # -> throws the same error
Sure, I can do:
#sync_to_async
def get_inviter(self, invite):
return invite.inviter
But, this is senile, if I have to do this for every queryset property call.
Is there a sane way to handle this?
Perhaps, there is a way to do this for all calls like that at once?
Yes, resolve the extra fields using select_related:
# Good: pick the foreign_key fields using select_related
user = await Invite.objects.select_related('user').aget(key=key).user
Your other string non-foreign such as strings and ints attributes should already
exist on the model.
Won't work, (although they feel like they should)
# Error django.core.exceptions.SynchronousOnlyOperation ... use sync_to_async
user = await Model.objects.aget(key=key).user
# Error (The field is actually missing from the `_state` fields cache.
user = await sync_to_async(Invite.objects.get)(key=key).user
Other examples for research
A standard aget, followed by a foreign key inspection yields a SynchronousOnlyOperation error.
I have a string key, and a ForeignKey user to the standard user model.
class Invite(models.Model):
user = fields.user_fk()
key = fields.str_uuid()
An example with alternatives that mostly don't work:
Invite = get_model('invites.Invite')
User = get_user_model()
def _get_invite(key):
return Invite.objects.get(key=key)
async def invite_get(self, key):
# (a) works, the related field is populated on response.
user = await Invite.objects.select_related('user').aget(key=key).user
async def intermediate_examples(self, key):
# works, but is clunky.
user_id = await Invite.objects.aget(key=key).user_id
# The `user_id` (any `_id` key) exists for a FK
user = await User.objects.aget(id=user_id)
async def failure_examples(self, key):
# (b) does not work.
user = await sync_to_async(Invite.objects.get)(key=key).user
invite = await sync_to_async(Invite.objects.get)(key=key)
# (c) these are not valid, although the error may say so.
user = await invite.user
user = await sync_to_async(invite.user)
# same as the example (b)
get_invite = sync_to_async(_get_invite, thread_sensitive=True)
invite = get_invite(key)
user = invite.user # Error
# (d) Does not populate the additional model
user = await Invite.objects.aget(key=key).user # Error
print(sync_to_async(invite.inviter)) # -> throws the same error
That's because it's equivalent to:
i = invite.inviter # -> throws the error here
af = sync_to_async(i)
print(af)
The correct usage is:
f = lambda: invite.inviter
af = sync_to_async(f)
i = await af()
print(i)
# As a one-liner
print(await sync_to_async(lambda: invite.inviter)())
Is there a sane way to handle this?
Perhaps, there is a way to do this for all calls like that at once?
(Disclaimer: Not tested in production.)
With nest_asyncio, you could do this:
def do(f):
import nest_asyncio
nest_asyncio.apply()
return asyncio.run(sync_to_async(f)())
print(do(lambda: invite.inviter))
Or take it even further:
class SynchronousOnlyAttributeHandler:
def __getattribute__(self, item):
from django.core.exceptions import SynchronousOnlyOperation
try:
return super().__getattribute__(item)
except SynchronousOnlyOperation:
from asgiref.sync import sync_to_async
import asyncio
import nest_asyncio
nest_asyncio.apply()
return asyncio.run(sync_to_async(lambda: self.__getattribute__(item))())
class Invite(models.Model, AsyncUnsafeAttributeHandler):
inviter = models.ForeignKey(User, on_delete=models.CASCADE, null=True)
...
# Do this even in async context
print(invite.inviter)
Does something like this work? Instead of invite.inviter you do await async_resolve_attributes(invite, "inviter")
#sync_to_async
def async_resolve_attributes(instance, *attributes):
current_instance = instance
for attribute in attributes:
current_instance = getattr(current_instance, attribute)
resolved_attribute = current_instance
return resolved_attribute
I am trying the generate PDF's for customers who successfully pays for an item but I keep getting this error.
No CustomerOrder matches the query
Below are my codes.
views.py
#staff_member_required
def admin_order_pdf(request, order_id):
order = get_object_or_404(CustomerOrder, id=order_id)
html = render_to_string('orders/pdf.html', {'order': order})
response = HttpResponse(content_type='application/pdf')
response['Content-Disposition'] = f'filename=order_{order_id}.pdf'
weasyprint.HTML(string=html).write_pdf(response, stylesheets=[weasyprint.CSS(settings.STATIC_ROOT + 'css/pdf.css')])
return response
urls.py
urlpatterns = [
path('', views.order_payout, name='order_payout'),
path('admin/order/<int:order_id>/pdf', views.admin_order_pdf, name='admin_order_pdf'),
path('confirm/', views.confirm_order, name='confirm_order'),
]
The get_object_or_404 method returns the message 'No object matches the given query' when it is unable to find any objects in the specified model using the given filter, which is id=order_id in this case.
Check this section from the documentation for more information on the function.
I'm trying to access user but getting an error when the view is async.
Code:
from django.http import JsonResponse
async def archive(request):
user = request.user
return JsonResponse({'msg': 'success'})
error message:
django.myproject.exceptions.SynchronousOnlyOperation: You cannot call this from an async context - use a thread or sync_to_async.
What I tried:
from django.http import JsonResponse
from asgiref.sync import sync_to_async
async def archive(request):
# user = sync_to_async(request.user)
# user = sync_to_async(request.user)()
# user = await sync_to_async(request.user)
user = await sync_to_async(request.user)()
return JsonResponse({'msg': 'success'})
Still getting the same error.
I want to access the user to check he/she has permission to archive a file.
EDIT:
I eventually figured out that I had to move it into a temporary method and run that as sync_to_async. I did this below:
def _check_user(request):
user = request.user
''' Logic here '''
return
async def archive(request):
await sync_to_async(_check_user, thread_sensitive=True)(request=request)
''' Logic here '''
And this seems to work, But not sure if this is the correct way of doing it?
Try this:
from django.http import JsonResponse
from asgiref.sync import async_to_sync, sync_to_async
#sync_to_async
def archive(request):
user = request.user
return JsonResponse({'msg': 'success'})
I don't know if it's really async, I'm trying to fix this problem too.
I've found something: https://www.valentinog.com/blog/django-q/
If the first option not work, see this link.
Since i am not able to login to https://www.duif.nl/login, i tried many different methods like selenium, which i successfully logged in, but didnt manage to start crawling.
Now i tried my luck with scrapy-splash, but i cant login :(
If i render the loginpage with splash, i see following picture:
Well, there should be a loginform, like username and password, but scrapy cant see it?
Im sitting here like a week in front of that loginform and losing my will to live..
My last question didnt even get one answer, now i try it again.
here is the html code of the login-form:
When i login manual, i get redirected to "/login?returnUrl=", where i only have these form_data:
My Code
# -*- coding: utf-8 -*-
import scrapy
from scrapy_splash import SplashRequest
from scrapy.spiders import CrawlSpider, Rule
from ..items import ScrapysplashItem
from scrapy.http import FormRequest, Request
import csv
class DuifSplash(CrawlSpider):
name = "duifsplash"
allowed_domains = ['duif.nl']
login_page = 'https://www.duif.nl/login'
with open('duifonlylinks.csv', 'r') as f:
reader = csv.DictReader(f)
start_urls = [items['Link'] for items in reader]
def start_requests(self):
yield SplashRequest(
url=self.login_page,
callback=self.parse,
dont_filter=True
)
def parse(self, response):
return FormRequest.from_response(
response,
formdata={
'username' : 'not real',
'password' : 'login data',
}, callback=self.after_login)
def after_login(self, response):
accview = response.xpath('//div[#class="c-accountbox clearfix js-match-height"]/h3')
if accview:
print('success')
else:
print(':(')
for url in self.start_urls:
yield response.follow(url=url, callback=self.parse_page)
def parse_page(self, response):
productpage = response.xpath('//div[#class="product-details col-md-12"]')
if not productpage:
print('No productlink', response.url)
for a in productpage:
items = ScrapysplashItem()
items['SKU'] = response.xpath('//p[#class="desc"]/text()').get()
items['Title'] = response.xpath('//h1[#class="product-title"]/text()').get()
items['Link'] = response.url
items['Images'] = response.xpath('//div[#class="inner"]/img/#src').getall()
items['Stock'] = response.xpath('//div[#class="desc"]/ul/li/em/text()').getall()
items['Desc'] = response.xpath('//div[#class="item"]/p/text()').getall()
items['Title_small'] = response.xpath('//div[#class="left"]/p/text()').get()
items['Price'] = response.xpath('//div[#class="price"]/span/text()').get()
yield items
In my "prework", i crawled every internal link and saved it to a .csv-File, where i analyse which of the links are product links and which are not.
Now i wonder, if i open a link of my csv, it opens an authenticated session or not?
I cant find no cookies, this is also strange to me
UPDATE
I managed to login successfully :-) now i only need to know where the cookies are stored
Lua Script
LUA_SCRIPT = """
function main(splash, args)
splash:init_cookies(splash.args.cookies),
splash:go("https://www.duif.nl/login"),
splash:wait(0.5),
local title = splash.evaljs("document.title"),
return {
title=title,
cookies = splash:get_cookies(),
},
end
"""
I don't think using Splash here is the way to go, as even with a normal Request the form is there: response.xpath('//form[#id="login-form"]')
There are multiple forms available on the page, so you have to specify which form you want to base yourself on to make a FormRequest.from_response. Best specify the clickdata as well (so it goes to 'Login', not to 'forgot password'). In summary it would look something like this:
req = FormRequest.from_response(
response,
formid='login-form',
formdata={
'username' : 'not real',
'password' : 'login data'},
clickdata={'type': 'submit'}
)
If you don't use Splash, you don't have to worry about passing cookies - this is taken care of by Scrapy. Just make sure you don't put COOKIES_ENABLED=False in your settings.py